OWC released a SandForce SF-2281 based 2011 MacBook Air SSD upgrade earlier this year in 120GB and 240GB capacities (the Mercury Aura Pro Express 6G). Using Hynix 2x-nm NAND (64GB packages with 8GB die) OWC is now shipping a 480GB version for $1149. If you need a ton of capacity for your MacBook Air, this is really the only solution.

Two drives died in less than one year. OWC keep sending me new ones and saying their driver hardly ever fails. Be aware!When it works it's really fast but it will not worse the hassle loosing all your data in every couple of month.

Be aware of issues. installed 480 GB SSD 6G and had 2 failures in less than 30 days - waiting for 3 one to be shipped. Response time is very slow. 3 weeks for first replacement and it failed in a week. first one was bad out of the box. I hope the 3rd one last a bit longer. They should reimburse you for the lost time for restoring 400GB of data.